Ar-15 lower parts kit includes: 1 bolt catch, 1 magazine catch, 1 pivot pin, 1 takedown pin, 1 magazine catch spring, 2 trigger pins, 1 buffer retainer, 1 magazine release button, 1 bolt catch spring, 1 buffer retainer spring, 1 selector hard detent, 1 selector soft detent, 2 take down/pivot detents, 1 bolt catch plunger, 1 bolt catch screw, 1 selector detent spring, 1 receiver pivot detent spring, 1 take down detent spring, 1 safety selector assembly (1 long paddle, 1 short paddle, 1 tumbler and 2 screws).Safety selector assembly only available in black with gun builders kit.